U.S. Pat. No. 5,087,183, issued on Feb. 11, 1992 to Edwards, the applicant of the present patent application, and entitled “Rotary Vane Machine with Simplified Anti-Friction Positive Bi-Axial Vane Motion Control” discloses a means for constraining, in a precision fashion, the circumferential motion of the vane so that the tip of the vane does not engage the inner bore of the stator housing, but is close enough to provide adequate gas sealing. Machines produced according to the '183 patent have significantly less friction than conventional contact vane machines. The Edwards '183 patent also discloses the use of roller bearings as the anti-friction element and includes use of one, two or three vanes.
Vane centering (attaining accurate axial positioning to avoid side contact between the vane ends and the stator endplates) is easily achieved through the use of ball bearings as taught, for example, in U.S. Pat. No. 5,374,172, issued on Dec. 20, 1994 to Edwards, and entitled “Rotary UniVane Gas Compressor.” Further, axially positioning through the use ball bearings is commonly used in both alternating and direct current electric motors as well as in contact-sealing vane compressors. Also made of record is U.S. Pat. No. 5,160,252 issued on Nov. 3, 1992 which is a continuation-in-part of the '183 patent.
In prior art multiple vane machines, the radial and tangential velocities of the vanes are constantly varying with respect to one another and, thus require the use of special segmented bearings that allow each vane to vary in speed independent of the other vanes. U.S. Pat. No. 5,374,172 issued on Dec. 20, 1994 to Edwards, discloses a single rotating vane machine. Unlike multi-vane machines of the prior art at the time, conventional dual race bearings are used to control the radial non-contact location of the single vane. Additionally, means are provided for dynamically balancing the rotating rotor and vane. Machines produced according to the '172 patent are characterized by having very low mechanical friction and excellent gas sealing, and are hence, very energy efficient.
U.S. Pat. No. 6,503,071 issued on Jan. 7, 2003 to Edwards, discloses a high-speed UniVane® fluid-handling device. This single vane gas displacement apparatus comprises a stator housing with a right cylindrical bore enclosing an eccentrically mounted rotor which also has a radial slot in which is movably radially positioned a single vane. The vane is tethered to antifriction vane guide assemblies concentric with the housing bore. Then vane has a pre-selected center of gravity located proximate to the housing bore axis. An option is to have a port in the vane for ducting high-pressure gas to the inlet side to react against the rotor slot to reduce vane contact therewith.
U.S. Pat. No. 6,623,261 issued on Sep. 23, 2003, also to Edwards, discloses a single-degree-of-freedom controlled-clearance UniVane® fluid-handling machine. In this patent, the rotor has a rotational axis and carries at least one vane which is supported by a vane guide apparatus for rotation about a stator axis which is spaced from the rotor axis a preselected amount and where both the rotor and vane have axial flat surfaces which are rotated adjacent to stationary flat surfaces of a stator or stator endplates. The patent discloses a provision for axial adjustment of the vane with respect to the flat surface of the stator endplates and independently provides an adjustment of the rotor end surfaces with respect to the stator end surfaces.
The single vane and double vane apparatus of the present invention embody two important distinctions from the prior art UniVane® patents (U.S. Pat. Nos. 5,374,172, 6,503,071, 6,623,261). First, roller bearings are used to control the radial position of the vane and second, axial positioning control rods or pins are used to dictate the axial position of the vane (its ‘centralization’) with respect to the rotor and the endplates. The prior art UniVane patents teach the use of a second set of ball bearings that simultaneously control both the radial and axial location of the vane and operate with respect to the stator endplates and not the rotor.
Unlike the prior art, the present invention teaches specific means to achieve the practical use of both a single vane and a dual vane device in which problems of dynamic balance and precision radial vane centering is achieved through the use of roller bearings; not ball bearings. The embodiments taught herein primarily encompass the application of precision rotor centering directly with respect to the stator housing, vane centering with respect to rotor (not the stator) and the dynamic balance design of the gliders required for practical single and dual vane devices.